Sand blast nozzle wiggler



Oct. 25, 1932. F. J. HULL I SAND BLAST NOZZLE WIGGLER Fileu Aug. 18, 1928 7 Sheets-Sheet l Oct. 25, 1932. F. J. HULL SAND BLAST NOZZLE WIGGLER Filed Aug. 18, 1928 7 Sheets-Sheet 2 Oct. 25, 1932. F. J. HULL SAND BLAST NOZZLE- WIGGLER glwuemtoz M 6 m w e Filed Aug. 18, 1928 Oct. 25, 1932.

F. .J. HULL 4 SAND BLAST NO ZmWr-GGLER Filed Aug. 1s, 1928 7 sneets-shejt 4 0d. 25, 1932. F! L; 1,883,917

SAND BLAST NOZZLE WIGGLER Filed Aug. 18, 1928 7 Sheets-Sheet 5 g: WU M g Inn's: 6 a a w f Q m fl E \\\&/ J

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F. J. HULL SAND BLAST NOZZLE WIGGLER Filed Aug. 18, 1928 7 Sheets-Sheet 6 Filed Aug. 18, 1928 7 Sheets-Sheet 7 center of rotation of the table.

Patented Oct. 25, 1932 V UNITED STATES PATENT OFFIQE'.

FOSTER J'. HULL, OF HAGERSTOWN, MARYLAND, ASSIGNOR T0 PANGBORN CORPORATION, OF HAGERSTOV] N, MARYLAN D, A CORPORATION OF MARYLAND SAND BLAST NOZZLE WIGGLER Application filed August 18, 1928. Serial No. 300,417.

The invention relates to sand blast apparatus of thetype in which a stream of abrasive propelled by air under pressure is projected from'a nozzle against the surface to be treated or abraded, which is most com monly, in the apparatus to which the invention relates, the surface or surfaces of castings which are being cleaned by the abrasive stream. i

I In the practice to which the invention particularly relates the nozzle or a group of nozzles is given a reciprocating motion, being'ordinarily swung or oscillated with a slow reciprocating arcuate motion, and while the work, which for convenience will be assumed'to be castings being cleaned, may be stationary, the castings are ordinarily moved slowly through the area covered by the abrasiv'e stream, the most convenient apparatus being a large rotary table, known asa sand blast table, which rotates with a slow motion carrying the castings through a chamber which overlies and encloses the work supporting surface of the table on one side of the The chamber, in turn, encloses the nozzle or nozzles and the entire area covered by the abrasive stream or streams.

The nozzles are ordinarily oscillated on an arc, the cord of which is located substantially on a radius of the table, the exact path of the nozzles being, however, more or less immaterial solong as it'carries the nozzles toward and from the center of the table.

A sand blast table of this general type equipped with the swinging nozzles referred to and particularly adapted for use in cleaning castings, is illustrated in myprior Patent No. 1,713,965.

The nozzles are ordinarily directed downwardly and the sand-blast stream or abrasive stream takes the form of acone or cones, the apex of each cone being at the nozzle.

A difliculty encountered in treating castings and other work in this way results from the fact that under some conditions, particularly where the work is high, i. e., extends upwardly from the table to a point in the vicinity of the nozzle and, therefore, intersects the conical stream where the cone is of them, the motor support and small diameter, narrow paths or channels appear on the surface of the work resulting from the concentration of the abrasive stream or streams on a small area of the surface being treated. The motion of the nozzle combined with the motion of the table passes this small abraded area or areas over the surface of the work, forming the paths referred to.

The object of the invention is to overcome this difficulty by spreading and enlar ing the cones, which makes the paths referred to much less distinct even where the work approaches close to the nozzles, and substan tially equalizes the entire area.

The spreading or enlargement of the cones and equalization of the abrasive action throughout the area covered by the abrasive stream from a group of nozzles or a single nozzle, is accomplished by imparting to the nozzle or group of nozzles, in addition to the slow reciprocating motion which, in the form of themachine shown, is an oscillation or swinging on an arcuate path, a secondary rcciprocating motion which is in thenature of I a vibration in that it is repeated many times for each primary reciprocation or oscillation. 7 i

This secondary motion is also preferably a reciprocating motion and it has come to be known in the art, so far as it is known and used, as a wiggle, the mechanism for imparting this motion being termed a'wiggler.

In the accompanying drawings I have illustrated a machine embodying the features of my invention in the preferred form. have also showna modified or secondary form of the invention which illustrates the application of the same principle in a slightly different form. 1

In the drawings:

Figure 1 is a top plan view of a sand blast table equipped with a group of nozzles and means for swinging the nozzles and also means for imparting a secondary motion to gear casing being removed.

Figure 2 is aside elevation of the nozzles and a portion of the nozzle arm adjacent the nozzles, the inner end of the arm being broken away.

and in Figure 3 at the right being identical fig.

.. 1 Referring to thedrawings so that the two figures constitute an elevationof the entire arm and mechanism 1mparting the secondary motion to the nozzles. g a Figure 4 is a top plan view of the outer end of the group of nozzles and the nozzle arm, the portion of these parts shown in Figure 4 being identical with, that shown in elevation in Figure 2.

Figure 5 is a top plan View of the inner end of-the arm and the actuating mechanism for imparting the secondary motion, the break where the arm is severedin Figures 4 and '5 being identically placed so that the two figures constitute a plan of the entire arm and secondary motion apparatus.

Figure 6 i-s'a diagrammatic view illustrating the effect of the secondary motion on the abrasive stream showing the nozzle in full lines in the center position of the secondary'moti'on and showing the same nozzle in dotted lines at each end of the secondary traverse, the stream in the three positions being also illustrated in a corresponding -man-. ner. I

Figure 7 is a vertical section through the nozzle arm at the swinging end where the nozzles are supported, the same being taken on the line 77 of Figure 4, the same showing the nozzle supports and pipes in elevation, the ends being'broken away.

Figure 8 is a view corresponding to Figure? showing .a single nozzle with the adjacent portion of the pipe and support, the

nozzle being shown in central vertical secthe line 8-8 of Figure 4.

Figure 9-is an elevation showing the pivotally mounted end of the rocker arm, includmg. a fragment of the lower end of the eccentricshaft and the ecentric pin.

FighrelO shows theeccentric shaft in sec tion on-the line 10 10 of Figure 9 looking down on the same fragmentof rocker arm,

Figure 11 is a seotion on the -line 11-11 of. Figure 10, showing the end of the eccentric shaft, also the eccentric pin and bearing and the eccentric slot in the rocker arm, the eccentric being, however, rotated from the position in .which it is shown in Figure 10.

Figure 12 is a top plan view-corresponding to Figure 5 showing a modified form of the mechanism for imparting'the' secondary motion tothe nozzles. This figure, however,.includes a somewhat greater area than is covered by Figure 5.

Figure 13 is a section on the. of FigureA. a

by numerals, each of which is used to indicate the sameor similar parts in the is rotated.

I which contains the chine shown in a general way intop plan in F igure'l'and to which the invention has been applied, though it is capable of more general application, comprises a rotary table 1 which is shown asof circular outline. This table is supported on suitable bearings,not shown, and driven in rotation in a horizontal plane about a central axis in any suitable manner, as by means of a motor2 on a stationary frame 1.3. This motor drives a worm gear 3 on a shaft 4 at .the'top of the machine, which shaft drives a'second shaft 5 by means of belt 6 andpulleys7, .8. This shaft, drives a worm 9, being connected to the worm shaft by a chain and sprocket gearing 1( The worm operates a worm wheel 11 which carries pinion 12 meshing with an annulus 14 secured to the table .and'by which the table The shaft 4 carries at its end near, but beyond, the center of the machine opposite the hich drives a chain worm.9' a sprocket 1.6 17 which, in turn, drives a sprocket 18 secured to'th'e shaft 19 which projects oirtwardly to the side of the machine opposite the pulleys 7 and 8. This shaft 19, in turn, a worm "20 meshing with worm wheel 20 so cured to the upright shaft 21, on which is mounted a ca m"22.; This cam, as shown, is provided with a depending peripheral flange 24 which isengaged on both sides by rollers-25. which rolilersa-re carried atthe outer swinging end o'f 'an arm 26 secured to an upright composite shaft 27. to be further described. to which is also secured the nozzle arm 28. Both the lower nn 'tion-mf the shaft 27 and the'arrn =28. in th'epreferred form of the invention shown. are hollow, serving as'ni-pes to lead compressed air to thenozzles; This'nozzle arm is supported intermediateh bv a roller 280' on the arm engaging a track 281 and it, carries at its outer end a group of sand-blast nozzles 30, to be more specifically described. I 7

These nozzles, and. the. arm 28 carrying them, see particularly Figure'2, are oscillated by the cam 22 and lever 26' described,swinging with a slow reciprocating motion an arc.the cord of which is substantially in .line with'the radius of the. table, the path of the nozzles being towardand from the center of the table and overlying the table; In accordance withthe operationof the sand 'blast table described in my prior Patent No. 1,713,965, the castingsare placed on the exposed portion of the table, indicatedbv reference. character 31, and carried through a stationary .enclosure orcovered portion. 32 nozzles 30, the chamber being elongated'inthe directionofthe circumierence rte-provide forthe removal of the abrasive' ifrom the work and the dropping of the same through the table," which is in the diflierent figures, the mar form of a grid as shown, before the castings are returned to the exposed portion 31, from which they are removed.

The oscillation of the nozzles, as described, is intended to cause the nozzles to cover a suflicientarea and to provide sufficient change of position and direction to cause the work to be treated with a fair degree of uniformity on all sides'and as to all exposed surfaces, however, as pointed out in the preamble, the stream of abrasive from each nozzle is substantially conical and particularly where the work'is high and projects upwardly to a point relatively near the nozzles the conical streams from the nozzles are intersected where the diameter of said streams is comparatively small so that they are inclined to form paths, i."e., narrow and elongated areas or channels on the surface of the work which are excessively abraded, other portions being cleaned or abraded to a less degree than is intended.

To avoid this effect and to equalize the abrasive action even at the points well above the table where the nozzles are located, it being understood that the nozzles are, in accordance with the prevailing practice, spaced well up from the table and directed downwardly, an additional or secondary motion, the oscillations described being referred to as the primary motion, has been imparted to the nozzles, the secondary motion being referred to in the trade as a wiggle, consists, in accordance with the preferred form illustrated, in a limited oscillatory or vibratory motion of the nozzles which is most conveniently a substantially arcuate motion about the end of the nozzle arm 28, this being the most convenient central point, as it is the point from which the pipes leading to the nozzles can most conveniently radiate. In accordance with the form of the machine illustrated, the group of nozzles 30 consists of four nozzles supported on any suitable frame 35, see Figures 2, 4 and 7. In the form of the invention shown, this frame is square, as seen in plan, carrying one of the nozzles 30 at each corner. It consists of four radiating arms 36, 37, 38, 39, the arms 36, 38 and 37, 39, being shown as forming the diagonals of the square frame, the respective radiating arms or members 36to 39 meeting at the center and each of said radial arms 36, 37 38, 39 is formed of an upper and a lower member 40 and 41.

The members 40 and 41 of each arm 36, 37, 38 and 39 are in the same vertical plane and are spaced apart vertically at the center ofthe machine and converge toward their ends at the corners of the frame where they support the nozzles and the ends of the flexible radiating nozzle pipes 42 to which the nozzles 30 are connected, each said nozzle, in the form of the invention shown, being turned downwardly and inwardly toward the center of the group of nozzles. The

braces or frame members 40 and 41 forming the arms 36, 37, 38, 39 are connected at the center, the top members 40 to a collar 43 and the lower members 41 to a collar 44, each of said collars being formed with a bearing 45 at the center, shown in the form of a ball bearing, and each said bearing has its inner member secured to a trunnion46 at the bottom and 47 at the top, the trunnions being vertical and in alignment and each being secured to the fittings 48.

In the form of the invention shown, the bottom journal 46 is formed on the end of a pin 49 which is seated atits upper end in a vertical bore 50 in the fitting 48, being adjustably secured in said bore by means of set screws 51 or in any suitable manner.

The bearing 45 and the collar 44 are sup-' ported on the end of the trunnion 46 by means of a washer or disk 52 and a nut 53 on a threaded reduced extension 54 of the stud 49 on which the shoulder carrying the inner bearing member is formed.

At the top the journal 47 is in the form of a stud suitably shouldered and threaded at its lower end to enter and engage the upper end of the member 48. In the form of the invention shown, the pipes 42 are flexible hose and the oscillation of the frame 35 relatively to arm 28 is taken up by the flexibility of these members. The corners of the frame carrying the nozzles are connected by tension bands 61 forming the sides of the square frame and secured at their ends to the nozzle supports 62, one for each nozzle, through which the shanks of the nozzles are passed and by which they are supported.

The end member or fitting 48 of the nozzle arm 28 is in the form of an elbow, having a horizontal arm with a' passage 63 secured to the end of the arm 28 by flanges 64 on both members connected by bolts 65. This portion 63 is in alignment with the main portion 28 of the arm. The member 48 also includes a vertical downwardly extending passage 66 at right angles to the portion 63 and at the lower end of the depending passage 66 are four laterally radiating passages 67. Flanged nipples 68 are secured to the member 48 at the ends of these passages 67 in any suitable manner, as by means of bolts 69. The respective nozzle pipes 42, shown in the form of pieces of rubber hose or other flexible tubing,- are secured to the nipples 68 in any suitable manner as by means of hose clamps 70.

The nozzles 30 are also provided with nipple-like extensions 71 to which the flexible pipes or hose 42 are connected by means of clamps or hands 7 2.

The vibratory motion, wiggling or oscillation of the nozzles 30 relatively to the arm 28 is accomplished by oscillating the frame 35, carrying the nozzles 30 upon the bearings 45, which bearings are carried by the end the frame 35 is,

necting members 'inember or end fitting 48 of the-nozzle arm 28.

The flexible pipes 42: provide for-and permit their oscillation. 1 This" oscillatory motion of in the form of the invention shown,communicatedthereto by way of con- 74 shown as-parallel to'the arm 28. These are preferably int'he form of these members 74 have adjacent fore and aft frame members36, 37,

38, 39', on:eachside. As shown, they are suspended fromthe upper rods 40 of each saidmember 37, 38, 39, 36 bymeans' of depending v brackets 77, see Figure 7.' V

the ends of the arm turned 4 means of transverse rods 77 ed at its center,

fitting'loosely about the The hose clamps 73 are accurately located in the direction of the radii of the frameby which, as shown, are threaded at their ends and seated at their inner endsin correspondingly threaded holes inthe member 48 on the respective sides thereof and being threaded at their. outer ends, through the strips 76 and into the respective hoseclamps 73. The rods 77 are held in position in the casting 48 by lock nuts 78.

The connecting rods or flexible tension members are secured at their ends opposite to the clamps 7 3 to a horizontally rocking arm 7 like a whiflietree, which is pivotally mountsee Figure 13, beneath the nozzle arm 28 at a point spaced'inwardly from the frame toward the center or shaft 27, about which the arm rocks. This arm is shown in-Figure 13 with the hose clamps 7 6, to which themembers 74 are secured at partially removed. These hose clamps are mounted on the opposite ends of the arm 75 in any suitable manner and are parallel to the nozzle arm 28. As shown in Figure 13,: the clamps 76, portions of which are broken away, are secured to the up-turned ends 77 of the arm 75.

To support the arm 75 at the center, as described, the nozzle arm 28 is provided with a split collar 7 9 encircling the arm, the bottom half 80 ofthis collar carrying a bearing 81 for the center of the arm 75 about which the arm swings substantially in a horizontal plane, the details of the bearing not being material to the present invention. .As shown, a'ball bearing is employed.

The inner bearing ring 82 of said bearing engages a stud 83, the upper end of which is seated in the lower half 80 of the collar and the outer bearing ring 83 isseated in a cup 84, the reduced shank 85 of which extends upwardly through the arm 7 5, the shank 85 stud 83. The cup 84 upper end 13 and the 'mesgam cap-.86 which is apertured to pass the reduced end 87 of thestud-83 whichv extends downwardly through a U. shaped depend ing member 88 formed on the lower half 80" of the collar 79, the extreme lower end of the stud being threaded and provided with a nut 89; -The bottom bar 90 of the U is prefer-- ably made'removable, as shown in Side elevation in Figure 2. Y

To vibrate or wiggle the nozzles 30, the arm 75 is oscillated or vibrated; This isaccomplished, in the preferred form of the in-* vention shown particularly in Figures 3 and 5, bymeans of an electric motor 92.

The motor 92 is, in theform of the'invention shown in said figures, provided with a motor shaft 93 on which is mounted a toothed gear 94 which meshes with a toothed gear 95 on the worm shaft 96, which worm shaft carries a worm 97 engaging a worm wheel, 98, see particularly Figures 3 and 5, which worm wheel 98'is mounted on and secured to a depending shaft 99, which shaft, see Figures 3 and 5, is provided at its lower'end with an" eccentric pin 100. The enclosed in a casing 144 having acover plate or gland145 through which the end of the shaft 99 protrudes. i

The depending eccentric pm 100 operates in a slot 101 extending in the direction of the length of, a lever arm 102 pivotally mounted at 103 on the bracket27, which connects the the shaft 27 in alignment to osc'illatetogether and supports the nozzle arm 28. The lever arm 102, in the form of the invention'shown,

extends outwardly beyond the slot 101 andis i. e.,' to the right in Fig curved backwardly,

at its extreme swinging ure 5, being formed end with a horizontally swinging pivot con nection comprising a vertical pin 104, to which is secured one end of connecting rod 105, the rod beingconnected atits opposite end to the. swinging arm 75 by means of a block 106 adjustably secured to the arm'by bolt 107 seated in an opening 107 in the arm 75, the rod being pivotally connected to the block 106 by pin 106 and there being preferably a series of said openings whereby the radius of the pin 106 about the bearing 81 may be adjusted, changing the relation of the swing of the arm 75 to and with the swing of the arm 102 and correspondingly varying the extent of the vibration of the nozzles.

F igures'9, 10 and 11 show in detail the cocentric pin 100 at the lower end of the shaft 99, which. eccentric pin is provided with a roller or rollers 108 supported on the pin by a ball bearing 109 and the slot 101 is shown as formed in a block110 secured to the lever arm 102. I

wormgear 97, 98, is

Iow'er hollowportion of Referring nowto Figure 3,-it will be noted FA stream of to lead the abrasive stream to the nozzle arm 28, is formed with a bracket 27 intermediate of its length, which bracket supports an upperisection to the shaft at 13 in alignment with the remainder of the shaft and that this upper section carries the cam arm 26 which oscillates the shaft 27 and the arm 28. The bracket 27 also carries a collar 114 which supports the arm 28 and the motor 92 is carried on a plate 112 secured to the upper end portion 13 of the shaft 27,. so that the motor 92 and all the parts operated thereby oscillate with-the arm 28 and the shaft 27 about the center of the latter shaft. l

Figure 12 is a plan corresponding to Figure 5 showing a modified form of the invention in which the wiggler motion is operated from the same source of power which operates the sand blast table instead of by a separate motor supported on the nozzle arm or nozzle arm shaft. This form of mechanical drive comprises a shaft 120 which is driven by a belt 121 and pulleys 122 and 12.3 or in any suitable manner, the pulley 123 being mounted on a continuously rotating shaft 124 correspondingtothe shaft 4 in Figure 1 and driven in the samevor any suitable manner from the source of power which rotates the table. This shaft 124 is also provided, in accordance with the illustration, with pulleys 125 which drive a belt 126 engaging and driving pulleys127 on the shaft 19, which operates the cam 24 by way of the worm 20 andworm gear 20 I The shaft 120 carries at its extremeend remote from the pulleys 122 a bevel gear 129 which meshes with and drives a bevel pinion. .130 mounted on a suitable bracket and carrying a sprocket 131'which drives a chain 132 which, in turn, engages and drives a sprocket 133 rotatably mountedon a bracket 134 corresponding to the bracket 27?. The sprocket 133 is secured to a shaft 136 which carries an eccentric pin 137 operating in a slot 138 in a lever 139, which corresponds to and closely resembles the lever 102 in the previous structure,which lever operates a connecting rod 105, as in the previousconstruction, the con necting rod being connected to a rocking arm 75 similar to that already described. Figure .6 illustrates diagrammatically a single nozzle 30 in central position and shows in dotted lines at 30 the extreme positions of the same nozzle on both sides of the central position. The figure also includes a diagrammatic illustration of the conical stream or blast 140 of abrasive projected'from the nozzle and the extreme positions of said stream at 140 on both sides of the central position.v The operation of the machine is believed to have been fully described in connection with the description of the details of the machine. It will, however, be reviewed in a generalway. abrasive is supplied in any suitable manner to the hollow portion 23 of the upright pipe 27 and is led thereby through the fitting 141 enclosed within the bracket 27 located intermediately of the pipe or upright 27, from which fitting it is delivered to the nozzle arm 28. This arm is shown as a pipe, though a passage for the abrasive stream along the arm may be provided in any suitable manner.

The nozzle arm 28 is oscillated slowly and continuously by means of the cam arm 26 at its upper end engaging the cam surfaces 24 by means of rollers 25 on the arm. The arm 28 and the bracket 27 with the upright shaft or pipe 27 carry all of the moving parts which constitute the wiggler motion and in this connection it will be noted that the shaft 99 is provided with bearings 135 supported on a secondary bracket 143 carried by said bracket 27 at the left in Figure 3, rotating in bearings 13 and 13", the latter shown fragmentarily and both supported on the machine frame. 7 1

The nozzle arm 28 carries the nozzle frame 35 at its extreme outer swinging end, the frame being mounted on the end of the nozzle arm to oscillate freely relatively thereto. The flexible pipes 42 which feed the nozzles from the fitting 48 at the end of the arm 28 provide for or permit the oscillation of the frame and nozzles, which is transmitted to the frame by way of flexible connections 74 from the rocking arm 75 operated through connecting rod 105 from the swinging arm 102, which is, in turn, operated by the eccentrio pin 100 at the bottom end of the shaft '99, already referred to as having bearings on the oscillating bracket 27 and driven through suitable gearing 94, 95, 96, 97', 98, from the motor. 92, also supported on the oscillating construct-ion, particularlyon the upper end of the shaft 27. Thus a secondary vibratory oscillating motion is imparted to the nozzles in addition to the slowprimary pendulumlike motion imparted to the nozzle arm 28 by the cam arm 26and cam surfaces 24. In this way the tendency to irregular action of the abrasive stream forming paths, particularly on the high work, portions of which approach closely to the nozzles, is completely eliminated and the nozzles thus operated effeet, .on the contrary, a uniform distribution of the projected abrasive.

Ihave thus described specifically and in detail a machine embodying the preferred and a modified form of my lnvention in order that the nature and the manner of using and applying the same may be fully understood, however the specific terms herein are used descriptively rather than in a limiting sense, the scope of the invention being defined in-the claims;

What I claim as new and desire to secure by Letters Patent is:

a. 1. The combinatlon with a sand blast carrier and means 'for operating the same to carry the work through the sand blast area and a nozzle of a nozzle arm mounted-to oscillate'transversely to the motion of the carrier and in a plane substantially parallel thereto, means foroscillating the arm imparting a slow laterally swinging motion thereto,'a support carrying said nozzle said supportbeing pivotally mounted on the swin end of the arm the axis of the pivot being substantially at right angles to the plane of oscillation of said arm, a rockingarm mounted on ,the/nozzle-arm and spaced inwardly from the support, flexible means connecting the 'rocking arm to the'support to oscillate the latter, rotary means oscillating with the arm and rotating relatively thereto, an eccentric membercarried by saidrotary means, a swinging lever oscillated thereby and a connecting rod connecting said rocking armto said swinging lever.

2. The combination with a sand fblast table of a nozzle arm, means for oscillating the arm laterally, of the table, a' nozzle and means carrying the-same andamounted to oscillate relatively to the arm about an axissubstantially at right angles to the plane ofoscillation of the arm, a "prime mover oscillating with thearm'and means including an adjustable lever connecting the same to the nozzle carrying means to oscillate the same imparting a secondary motion to the nozzle.

3. In a sand blastapparatushaving means formoving articles to be treated through the blasting zone, a plurality o'fconverging nozzles spaced apart, means for moving the nozzlesby a slow motion transversely to the dizone, a nozzle arm to said support and in a parallel" to the motion o-fthe support and of rection of motion of the work, means for oscillating the nozzles-about an axis-which issubstantla'lly parallel to .thegeneral direction of the nozzles and which is substantially atiright angles to the motion of the work and the,

transverse motion of the nozzles. y y

4. In a sand blast machine havin means for moving the workthrough the lasting mounted to reciprocate transversely to the direction of motion of the work and in aplanesubstantiallyparallel to the path of the work, means for reciprocating the arm as aforesaid, a plurality of nozzles pivotally mountedin converging relationon-thearm'to oscillate together relatively plane substantially the work, and means for, oscillating the nozzle relatively to the support as aforesaid.

5. In a, sand blast machine having means for moving the work through the blasting zone, a nozzle arm mountedtooscillatetransversely to the directionof motion ofthe-work, means for oscillating'the arm-as aforesaid, a plurality of nozzles in angular relation to each other-and arsupport therefor pivotally mounted on the arm to oscillate relatively to said arm and inv a plane substantially .p'aral parallel to "its motion, the-arm with aslow motionabout said pivot, i

maeaow f lel to ithe planeiofoscillation of the armlnfl :meansoroscillating the support relativelry tothe-arm as aforesaid, said comprisingra centrally pivoted rocking :leve'r carried by the arm,;flex1bleimeans-connecting "general-direction asthe axis of "the arm, n'nd means 'for'impartingia vibratory oscillation to the nozzle support about :its axis-and rel tively to the arm, the "nozzle bein disposed *hsixbstantially the directiono'ffl :axisof its' s'upport. i

7. iIna sand blast apparatus a carrier' for thework and i a nozzle arm pivoted'fto' swing transversely to the motion of the carrier and in aplene means for sw inging a nozzle support near theendof the arm-and a nozzle on said support, the support being pivotally mountedon the arm to swingabout an axissubstantially parallel to the axis of 'the-arm,' and means for imparting a vibrator ;oscillation of the nozzle about "said axis d relatively to" the arm, said vibrating means comprising two flexible tension mem- :bers spaced apar't'and secured atone end fo the *SIIPEOBQIH. pivotally mounted cross arm t0- Wh1C {they are connected at their-0pm site "ends, a conne( :ting rod atone endto'said cross arm and means mounted-on theswinging arm near its axis for vibrating the connecting rod in the direction of 'its length. a v 8. In a sand blast machine a work carrier and a nozzle carriermounted to reci te transversely to the path of' 'the work carrier, a support "and a plurality of nozzles on said support, thesupportbemg mounted on the carrier to oscillate relatively thereto, the

nozzles converging in *the direction of the axis of oscillation of the support, means for reciprocating the nozzle carrier and means for vibrating the nozzle support relatively to'the nozzle carrier with a rapid -osoilla'tory motion.'--

9. In a sand blast machine 'a nozz'le earrier and a workcarrier, means for moving the workcarrier, and means for moving "the nozzle con-rier transvensely'to "the work *carrier,-ra mozzle', a :support for the "samefsaid support being :pivotally mounted on the 1102'- zle roam-rier, the :nozzle 'being disposed in the means for moving the carrier,

oscillating means general direction of the axis of the support, and means for vibrating the nozzle support with an oscillatory motion about said axis.

10. In a sand blast machine a nozzle carrier and a Work carrier, means for moving the Work carrier, and means for moving the nozzle carrier transversely to the Work carrier, a nozzle, a support for the same, said support being pivotally mounted on the nozzle carrier, the nozzle being disposed in the general direction of the axis of the support, and means for Vibrating the nozzle support With an oscillatory motion about said axis, said oscillating means comprising a motor mounted on the nozzle carrier and a connecting rod connecting the motor to said osci1 lating support.

Signed by me at Hagerstown, Maryland, this 10th day of August, 1928.

FOSTER J. HULL. 

